CN104063836B

CN104063836B - Image inspection equipment, image review systems and image checking method

Info

Publication number: CN104063836B
Application number: CN201410272801.3A
Authority: CN
Inventors: 北井正
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2013-03-15
Filing date: 2014-03-13
Publication date: 2018-01-30
Anticipated expiration: 2034-03-13
Also published as: CN104063836A; JP2014199250A; US20140268259A1; US9106771B2; JP6357786B2

Abstract

Image inspection equipment, including：Image acquisition unit is read, obtains the reading image for the image for being formed and being exported；Check image generation unit, the information based on the image that formed and exported obtained from image processing apparatus and generate the check image that image is read for checking, the image processing apparatus is according to the density of the state correction image of image processing system and generates information；With inspection result acquiring unit, it obtains the determination result for reading the defects of image based on check image and the difference read between image.Check image generation unit obtains density correction information, and the density of wherein image, which is corrected front and rear density value, to be associated, and the generation of the density correction information based on acquisition corresponds to the check image before density is corrected.

Description

Image inspection equipment, image review systems and image checking method

Technical field

The present invention relates to image inspection equipment, image review systems and image checking method.

Background technology

Generally, the inspection of print paper (printed sheet) is carried out by hand；However, in recent years using pair Printed sheets carry out the equipment for checking the post processing as lithographic printing.It is this inspection equipment first by read by by hand from The flawless image generation chosen in the reading image of print paper refers to master image.Then, master of the equipment to generation is checked The appropriate section of the reading image of a part for image and print paper to be detected is contrasted, and is based on being somebody's turn to do with master image Partial diversity factor determines whether print paper has defect.

However, it is particularly suitable for without version printer, such as electrophotographic printer (it is widely used in recent years) Print a small amount of copy, and for example, in the case where variable data prints, it is often the case that the printing content of every page not phases Together；Therefore, it is inefficient to generate master image from print paper as offset press and be compared using master image.For This problem is tackled, master image can be generated from print data.This makes it possible the printing of efficient process variable data (for example, with reference to international patent application No.2002-531015 open source literature in Japan).

Meanwhile in image processing system, even in the case of the copy based on identical image output, due to paper The aging blemiss copy that the image for providing developer forms engine may have different density.For example, taking above-mentioned electronics In the case of the image processing system of photographic system, due to the degeneration of light source for exposing photoreceptor or for electrostatic latent image Degeneration of developing bias developed, etc., density may reduce.

In order to overcome this problem, the predetermined density pattern of printing colour code can be used and according to each of the colour code of printing The method that the reading calibration of the output results of density inputs the density to the image information of engine (discloses for example, with reference to Japanese patent application No.H8-289149)。

Above-mentioned master image is preferably based on input and generated to the image of engine, to reduce as far as possible because image procossing causes Influence.On the other hand, when the density of the image of input to engine discloses No. H8-289149 disclosure using Japanese patent application Technology carry out timing, based on reflection correction result image generate master image.

Correction of the above-mentioned input to the image of engine is performed, with by the way that consistently supply developer keeps generating from engine In the density of the image on paper.On the other hand, when the image of the result based on reflection density correction generates master image, generation Master image density according to correction change, the variable density cause by read output paper obtain reading image and master map Density contrast as between.As a result, even if image does not have defect, due to variable density, image may be confirmed as with defect.It is attached Band ground, this problem are likely to occur in the image in the conventional recording medium in paper and such as film is formed and is exported.

Accordingly, it would be desirable to be able to which generation corresponds to the master image of the density correction for the image to be formed and exported in systems, should System by will be read by readings image that paper obtains and image for inspection contrasted and check image formed with The result of output.

The content of the invention

It is an object of the invention to solve the problems of the prior art at least in part.

Image inspection equipment, check the reading image that the image for being formed and being exported on paper by reading obtains.The figure As checking that equipment includes：Image acquisition unit is read, obtains the reading image that the image for being formed and exporting by reading generates； Check image generation unit, the information based on the image that formed and exported generate the check image that image is read for checking, The image processing apparatus of the information for the image that the information will be formed and exported from generation obtains；With inspection result acquiring unit, its Based on check image and the difference between image is read, obtains the determination result for reading the defects of image.Image processing apparatus, According to the density of the state correction image to be exported for the image processing system for carrying out image formation and output, to be formed with generation With the information of the image of output.Check image generation unit obtains density correction information, and the density of image is by image in the information The front and rear density of processing unit correction is associated, and the generation of the density correction information based on acquisition corresponds to by image procossing The check image of density before device correction.

Image review systems, check the reading image obtained by reading the image for being formed and being exported on paper.Image Inspection system includes：Image processing apparatus, it is defeated according to the state correction for the image processing system for carrying out image formation and output The density of the image gone out, and generate the information for the image that formed and exported；Image formation unit, based on what is formed and exported The information of image carries out image formation and output；Image fetching unit, by reading the paper formed thereon with output image Zhang Shengcheng reads image；Check image generation unit, the information based on the image that formed and exported generates to be read for checking The check image of image；With inspection result acquiring unit, it is obtained and read based on check image and the difference read between image The determination result of the defects of image.Check image generation unit obtains density correction information, the density of image in the information It is associated by the front and rear density of image processing apparatus correction, and the generation of the density correction information based on acquisition is corresponded to and schemed The check image of density before being corrected as processing unit.

Image checking method, check the reading image that the image for being formed and being exported on paper by reading obtains.Image Inspection method includes：Obtain the reading image that the image for being formed and exporting by reading generates；Obtained from image processing apparatus The information for the image for being formed and being exported, the image processing apparatus is according to the state correction of the image processing system image to be exported Density, the image processing system carries out image formation and output, and generates the information for the image that formed and exported；From image Processing unit obtains density correction information, and the density in the information before and after the density of image is corrected is associated 's；The information generation of density correction information and the image that formed and exported based on acquisition is filled corresponding to density by image procossing Put the check image before correction；And obtain based on check image and the difference read between image and read the defects of image really Determine result.

When connection with figures considers, by reading the detailed further below of currently preferred embodiment of the invention, the present invention Above and other purpose, feature, the meaning in advantage and technology and industry may be better understood.

Brief description of the drawings

Fig. 1 is the signal for the structure for showing the image formation system including inspection equipment according to an embodiment of the invention Figure；

Fig. 2 is the block diagram for the hardware configuration for showing inspection equipment according to an embodiment of the invention；

Fig. 3 is shows DFE according to an embodiment of the invention, engine controller (engine controller), printing Engine, the block diagram for checking equipment and each functional configuration of after-treatment device；

Fig. 4 is the schematic diagram for showing the relatively pattern of test according to an embodiment of the invention；

Fig. 5 is the schematic diagram for the structure for showing print engine according to an embodiment of the invention；

Fig. 6 is the schematic diagram for the example for showing gray scale according to an embodiment of the invention (gradation) checking list；

Fig. 7 is the example of the colour code exported in the generating process for show gray correction table according to an embodiment of the invention Schematic diagram；

Fig. 8 is the example of the reading result table of the result for the colour measurement for showing colour code according to an embodiment of the invention Schematic diagram；

Fig. 9 is to show pair between colour code according to an embodiment of the invention and the preferably pattern density of reading result The schematic diagram for the desired result table that should be related to；

Figure 10 is the flow chart for the operation for showing inspection equipment according to an embodiment of the invention；

Figure 11 is the block diagram for the functional configuration for showing master image processing unit according to an embodiment of the invention；

Figure 12 is the flow chart for showing master image generation operation according to an embodiment of the invention；

Figure 13 is the schematic diagram for the example for showing smothing filtering；

Figure 14 is the schematic diagram for the example for showing inverse (inverse) gray correction table according to an embodiment of the invention；

Figure 15 is the flow chart for showing master image generation operation according to another embodiment of the present invention；

Figure 16 A and 16B show angle point grid according to an embodiment of the invention (corner extracting) wave filter Result example schematic diagram；With

Figure 17 is the flow chart for showing inverse gray correction operation according to another embodiment of the present invention.

Embodiment

The exemplary embodiment of the present invention is explained in detail below with reference to the accompanying drawings.In the present embodiment, describe including The image review systems of equipment are checked, it reads reading image and the master image check image shape that output result obtains by comparing Into the output result with output, and explain in image review systems, when the density of raw image data is according to image shape When being adjusted into the change of the state of device, how master image is generated.Fig. 1 is a schematic diagram, is shown according to this The overall structure of the image formation system of embodiment.As shown in figure 1, before including numeral according to the image formation system of the present embodiment Hold (DFE) 1, engine controller 2, print engine 3 and check equipment 4.

DFE1 is image processing apparatus, its generate the view data to be printed, i.e. the print job based on reception and The dot matrix diagram data of the image of output, and the dot matrix diagram data generated is exported to engine controller 2.In addition, according to this implementation The DFE1 of example adjusts the density for the dot matrix diagram data to be generated according to the change of the state of print engine 3, and the print engine 3 is figure As forming apparatus.

Engine controller 2 is controlled print engine 3 and print engine 3 is performed based on the dot matrix diagram data received from DFE1 Image is formed and output.In addition, when checking that equipment 4 checks the result that the image performed by print engine 3 is formed and exported, root According to the engine controller 2 of the present embodiment using the dot chart data transfer received from DFE1 to inspection equipment 4 as checking ginseng The information of the original paper for the image examined.Now, engine controller 2 also by the information transfer of gray value table to equipment 4 is checked, use by the table In the density adjustment that DFE1 is carried out.

Print engine 3 is image processing system, and it is based on dot matrix diagram data according to the control of engine controller 2 and performed Image on paper is formed and output, and the paper is recording medium.By way of parenthesis, except above-mentioned paper, any flaky material, such as Film (film) or plastics are all used as the recording medium, as long as image can on the material be formed/exported.Check equipment 4 It is image inspection equipment, it generates master image based on the dot matrix diagram data inputted from engine controller 2.Now, the base of equipment 4 is checked The density of image is adjusted in the information of the gray value table received from engine controller 2.The step is necessity of the present embodiment Aspect.Then, check equipment 4 by the way that the reading image of the paper generation exported from print engine 3 will be read by reading equipment Contrasted with the master image of generation and check output result.

When checking that equipment 4 confirms that output result has defect by master image and the contrast read between image, check The notification engine controller 2 of equipment 4 instruction page is determined as defective information.So as to which engine controller 2 performs and reprints this The control of defect page.

Herein, reference picture 2 explains composition according to the engine controller 2 of the present embodiment, print engine 3 and checks equipment 4 The structure of the hardware of each functional block.Fig. 2 is the block diagram for the hardware configuration for showing the inspection equipment 4 according to the present embodiment.To the greatest extent Pipe Fig. 2 shows the hardware configuration for checking equipment 4, and engine controller 2 and print engine 3 have with checking that equipment 4 is much the same Hardware configuration.

As shown in Fig. 2 had and common information processor such as individual calculus according to the inspection equipment 4 of the present embodiment Machine (PC) or server identical structure.Especially, CPU (CPU) is included according to the inspection equipment 4 of the present embodiment 10th, random access memory (RAM) 20, read-only storage (ROM) 30, hard disk drive (HDD) 40 and interface (I/F) 50, and These hardware componenies are connected by bus 90.In addition, I/F50 be also associated with liquid crystal display (LCD) 60, operating unit 70 and specially With equipment 80.

CPU10 is arithmetic element, and controls the whole operation for checking equipment 4.RAM20 is being capable of high speed information read/write behaviour The temporary storage medium of work, and it is used as working region in CPU10 processing informations.ROM30 is read-only permanent storage media, And the program of such as firmware has been stored in ROM30.HDD40 is the permanent storage media for being capable of reading/writing of information operation, and Operating system (OS), different control programs and application program etc. have been stored in HDD40.

Bus 90 and each hardware and network etc. are connected by I/F50, and control these connections.LCD60 is a visual use Family interface, for making user check the state of equipment 4.Operating unit 70 is a user interface, such as keyboard and mouse, is used Family inputs information by the operating unit to inspection equipment 4.

Special equipment 80 be for realize engine controller 2, print engine 3 and check equipment 4 each in it is special The hardware of function；In the case of print engine 3, special equipment 80 is the transmission mechanism for transmitting paper or the shape on paper Into the draught machine of/output image ,/output image is formed on the paper.In addition, in engine controller 2 and check equipment 4 In the case of, special equipment 80 is special arithmetic facility, for high-speed cruising image procossing.The arithmetic facility is by for example specific use Way integrated circuit (ASIC) forms.In addition, special equipment 80 includes reading equipment, for reading the image exported on paper.

In this hardware configuration, it is stored in recording medium, such as ROM30, HDD40 or CD (not shown) Program is loaded in RAM20, and CPU10 performs operation according to the program, so as to set up software controlled unit.Realize basis The engine controller 2 of the present embodiment, print engine 3 and check equipment 4 function functional block it is soft by what is formed by this way The combination of part control unit and hardware is formed.

Fig. 3 is to show the DFE1 according to the present embodiment, engine controller 2, print engine 3 and each work(for checking equipment 4 The block diagram of energy structure.In figure 3, transmission/reception of data is represented by solid line, and the flowing of paper is illustrated by the broken lines.Such as Fig. 3 institutes Show, job information processing unit 101, RIP processing units 102 and gradation data generation unit are included according to the DFE1 of the present embodiment 103.Engine controller 2 includes data capture unit 201, engine control unit 202 and dot chart transmission unit 203.Printing is drawn Holding up 3 includes print process unit 301.At checking equipment 4 including reading equipment 400, reading image acquisition unit 401, master image Reason unit 402, check control unit 403 and compare test cell 404.

Job information processing unit 101 based on outside DFE1 via network inputs print job or pass through operate generate Print job control image formed and output execution, the operation is based on the picture number being stored in DFE1 by operating personnel According to what is made.In the execution that image generates and exports, job information processing unit 101 makes RIP processing units 102 be based on including View data generation dot matrix diagram data in print job, and by the dot chart data input of generation to data capture unit In 201.

RIP processing units 102 generate according to the control of job information processing unit 101 and are based on including for print engine 3 View data in print job performs the dot matrix diagram data that image is formed and exported.Dot matrix diagram data be composition to be formed/ The information of the pixel of the image of output.According to the print engine 3 of the present embodiment in cyan (C), magenta (M), yellow (Y) and black Image is formed on the basis of the binary picture of color (K), and exports the image of formation.On the other hand, it is included in print job View data is typically the image with a large amount of levels (levels), wherein each pixel is represented as gray value, the gray scale Value is in the range of such as 256 gray values.So as to the view data that RIP processing units 102 will be included in print job The image with a small amount of level is converted to from the image with a large amount of levels, and generates the dot matrix diagram data of CMYK binary pictures.

In the generation of dot matrix diagram data, based on the gray correction table generated by gradation data generation unit, RIP processing is single Member 102 adjusts the density of image.Based on colour code (color patches) colour measurement result, gradation data generation unit 103 generate gray correction table by being connected to DFE1 colorimeter 110, and the gray correction table of generation is inputted to RIP processing Unit 102.The density that RIP processing units 102 are used for image adjusts gray correction table used by job information processing unit 101 With being inputted together with dot matrix diagram data to engine controller 2.The reading of the colour code carried out by colorimeter 110 and by gradation data The generation of the gray correction table of generation unit 103 will hereinafter be described.

Data capture unit 201 obtains the dot matrix diagram data and gray correction table from DFE1 inputs, and makes engine control list Member 202 and dot chart transmission unit 203 operate.Engine control unit 202 makes print engine 3 be based on from data capture unit 201 The dot matrix diagram data of transmission is formed and output image.The dot matrix that dot chart transmission unit 203 will be obtained by data capture unit 201 Diagram data and gray correction table are transmitted to equipment 4 is checked, to generate master image.

Print process unit 301 obtains the dot matrix diagram data inputted from engine controller 2, and figure is formed on print paper As and the print paper is exported.Print process unit 301 according to the present embodiment is by a common electrophotographic image shape Realized into mechanism (mechanism)；It is also possible, however, to use other kinds of image formation mechanism, such as inkjet type.

In addition, in order to optimize the density of the dot matrix diagram data of input according to the change of image density, the change is due to set Standby condition over time or the deterioration of operating environment and it is caused, will be by color according to the print process unit 301 of the present embodiment The colour code output that degree meter 110 is read, so as to generate above-mentioned gray correction table on paper.This will hereinafter be described.

It is an image fetching unit to read equipment 400, and it reads shape on the print paper exported by print process unit 301 Into image, and data output will be read.Reading equipment 400 is, for example, being installed on the line in the transmission path for checking equipment 4 Scanner, the print paper exported by the transmission path from print process unit 301 are transmitted, and are read equipment 400 and passed through Read the image being formed on print paper surface in the surface for scanning the print paper being transmitted.

The reading image generated by reading equipment 400 is the target checked by inspection equipment 4.It is to pass through to read image The image of the Surface Creation for the print paper that output is formed by image is read, so as to be the image for illustrating output result.Read Image acquisition unit 401 obtain read image information, the reading image by reading equipment 400 read print paper surface and Generation.The information of the reading image obtained by reading image acquisition unit 401, which is input to, compares test cell 404, so as to enter Row is relatively tested.By way of parenthesis, will read image and input to test cell 404 is compared is according to the control for checking control unit 403 And perform.Now, check that control unit 403 obtains and read image, then will read image and input to comparing test cell 404。

As described above, master image processing unit 402 obtains the dot matrix diagram data inputted from engine controller 2, and generate master Image, the master image are the image for being used to check compared with the image to be checked.In other words, master image processing unit 402 are used as the check image generation unit based on the image to be exported generation master image, and the master image is for reading image The image for being used to check checked.The master image generation processing carried out by master image processing unit 402 will be retouched in detail below State.

Checking control unit 403 is the control unit of the whole operation for checking equipment 4 of control, and is included in and checks equipment 4 In unit according to check control unit 403 control operation.Comparing test cell 404 will be from reading image acquisition unit 401 The reading image of input is compared with the master image generated by master image processing unit 402, and image expected from determination is formed Whether it has been performed with output.Compare test cell 404 to be made up of ASIC, substantial amounts of calculate is handled with quick.In the present embodiment In, check that the control ratio of control unit 403, for use as image inspection unit, also serves as acquisition by comparing test compared with test cell 404 The test result acquiring unit of the result for the test that unit 404 is carried out.

Compare test cell 404 by be expressed as the 200-dpi of 8- positions rgb value reading image and master map as described above As being compared on the basis of pixel for pixel, and each 8- positions rgb pixel value is calculated on the basis of pixel for pixel Difference between the respective pixel values in master image.The difference calculated by this way and with the magnitude relationship of threshold value On the basis of, check that control unit 403 is determined on image is read presence or absence of defect.In other words, control unit is checked 403 controls are included in the unit checked in equipment 4, so as to be used as image inspection unit.

By way of parenthesis, in the comparison between image and master image is read, check control unit 403 by it is as shown in Figure 4 by The zoning that given area size marks off in master image is superimposed upon the portion corresponding to the zoning for reading image On point, and the margin of image element of each pixel is calculated, i.e., the density contrast of each pixel.This processing is by inspection control unit 403 Extract master image and read the image of each overlap-add region of image and be input to the image extracted and compare test cell 404 And realize.

In addition, the position for reading the zoning being superimposed on image is moved in the vertical and horizontal direction, i.e. mobile to read The region of image from vertically and horizontally upper extraction image, inspection control unit 403 to determine extraction region, in this region The total value of the difference calculated is corresponding to the extraction superposed positions in the extraction region of master image, i.e. reads the corresponding of image-side The minimum value in region is extracted, and from counted difference between the pixel in the extraction region determined as comparative result.

As shown in figure 4, each grid (grid square) is the region that each pixel value difference is summed.In addition, Fig. 4 Shown each zoning is dimensioned, for example, based on the comparison test cell 404 being made up of as described above ASIC Can compared pixels value at once region.

Another method, it is that a kind of each pixel of determination is normal or defective method, the determination is based on calculating Result of the difference of each pixel gone out compared with threshold value, and will be confirmed as the count value of defective pixel with it is pre- If threshold value be compared.In addition, replace determining to whether there is defect on each above-mentioned zoning, it may be determined that on each Pixel is presence or absence of defect.

By this processing, the zoning of master image is alignd with reading the appropriate section of image, then calculating difference.With Afterwards, when the zoning of master image is moved into aligned position, compare test cell 404 export moves vertically and horizontally measure with And the difference of pixel.For example, even if the diminution ratio entirely read between image and whole master image is different, as shown in figure 4, than Influenceing for example can be by dividing master image and by the zoning of master image to reading the corresponding of image with given area size Section aligned and reduce.

In addition, the adjacent area in the region divided as shown in Figure 4 is estimated as approximation relatively on the amount of movement of position 's.Therefore, when the comparison test on each zoning on each zoning calculating difference by realizing, rather than Imaging importing whole will be read to master image and calculating difference and realizing is, by performing computing, using by being used as center The comparison test defined location amount of movement of adjacent area moves the lap position of zoning in the vertical and horizontal direction, i.e., It is reduced the lap position movement in the vertical and horizontal direction of operand, zoning, at accurate lap position Computing be more likely performed, can be reduced so as to total operand.

By way of parenthesis, as the method for comparing the magnitude relationship between difference and threshold value, controlled according to the inspection of the present embodiment Unit 403 is by the difference by comparing the counted each pixel of test cell 404 compared with default threshold value.So as to check Whether each pixel value difference that control unit 403 is obtained between instruction master image and reading image exceeds the information of predetermined threshold value As comparative result.In other words, it is whether defective that the pixel that each composition reads image can be tested.In addition, shown in Fig. 4 Each zoning is dimensioned, for example, can be compared at once based on the comparison test cell 404 being made up of as described above ASIC Compared with the region of pixel value.

In the above-described embodiments, an example is described, wherein comparing the pixel that test cell 404 calculates composition master image The difference between each pixel of image is read composition, and exports counted difference, and check control unit 403 by difference with Threshold value is compared.Or compare test cell 404 and can be configured to by difference compared with threshold value, and check that control is single Member 403 can obtain result of the comparison, i.e. each pixel, the instruction picture corresponding in master image of image are read on composition Element difference whether beyond predetermined threshold value information.Therefore, check that the comparison processing of control unit 403 is transferred to compare Test cell 404, it is thus possible to high speed processing is obtained by using hardware.

Then, each machinery knot of print engine 3, inspection equipment 4 and stacker (stacker) 5 will be explained with reference to figure 5 Structure and paper transport path.As shown in figure 5, it is included in the print process unit 301 in the print engine 3 according to the present embodiment With a structure, photosensitive drums (photosensitive drums) 12Y, 12M, 12C and 12K (hereinafter, quilt in the structure Be referred to as " photosensitive drums 12 ") set along transmission belt 11, and be so-called tandem, the transmission belt 11 is loopy moving dress Put.That is, multiple photosensitive drums 12Y, 12M, 12C and 12K are set along transmission belt 11, and the transmission belt is an intermediate transfer, thereon Formed with the intermediate transfer pattern that be transferred on the paper (example of recording medium) conveyed by dielectric disc 13, wherein, passing Sequentially formed on defeated direction from the upstream side of transmission belt 11.

Y, M, C and K toner image for the development being formed on the surface of photosensitive drums 12 are transferred in transmission belt 11 successively, with Just overlap each other, so as to form full-colour image.The full-colour image being formed in transmission belt 11 is transferred on paper by transfer roll 14 On the position opened, in the closest paper being illustrated by the broken lines in Figure 5 of the full-colour image that the opening position is formed in transmission belt 11 Open the paper transmitted in transmission path.

The paper for being already formed with image thereon is further transmitted, and the image is fixed rod 15 and is fixed on paper, Then, the paper, which is transmitted into, checks equipment 4.In the case of duplex printing, image has been formed and has been fixed at one Paper on side is transmitted into reversing paths 16, and is inverted wherein, is then transferred to the transfer position of transfer roll 14 again Put.

Read equipment 400 and the paper transmitted from print process unit 301 is read in the paper transport path for checking equipment 4 Both sides, and generate and read image and export the reading image to image acquisition unit 401 is read, the reading image obtains single Member is made up of the information processor in inspection equipment 4.In addition, the paper read by reading equipment 400 is further set in inspection Transmit, and be transmitted into stacker 5 in standby 4, be then discharged into and replicate in take-up reel 501.By way of parenthesis, in Figure 5, as Example, read equipment 400 and be arranged in the paper transport path for checking equipment 4, only on the side of paper；However, two readings Taking equipment 400 may be placed on the both sides of paper, so as to check the both sides of paper.

Then, explain how gradation data generation unit 103 generates gray correction table.Fig. 6 is shown according to this implementation The chart of the example of the gray correction table of example.As shown in fig. 6, it is association according to the gray correction table of the present embodiment (associates) with 8- place values represent from 0 to 255 256 " input gray level values " each and CMYK " output gray levels The table of value ".In other words, it is for the state correction dot chart according to print engine 3 according to the gray correction table of the present embodiment The density correction information of the density of data, and be the information on the association between the density before correcting and after correction.

It is the dot chart that will be inputted in print process unit 301 according to the density correction of the present embodiment purpose The density of data be adjusted so as in advance it is higher, so as to overcome due to the print process unit 301 of print engine 3 aging deteriorate cause Output image density reduce.Therefore, as shown in fig. 6, " the input gray level value " of from " 253 " to " 255 " is all converted into maximum Output gray level value " 255 ".In addition, for example, when input gray level value is " 3 ", all it is converted into all CMYK colors The gray value of " 5 ".

Fig. 7 is an example for showing colour code, and the colour code is exported by print process unit 301, and is read by colorimeter 110 Take, so that gradation data generation unit 103 generates gray correction table.As shown in fig. 7, according to the colour code of the present embodiment be with Density from 10% to 100% is formed at the CMYK block figures on paper.

The position of block shown in Fig. 7 is pre-set, and colorimeter 110 measures the image shown in Fig. 7 in precalculated position Density.As a result, gradation data generation unit 103 store by colorimeter measure result, so as to corresponding on paper Each percentage association of the measurement density of position.Fig. 8 is the example for showing the measurement result information generated in this way The chart of son (hereinafter, referred to as " reading result table ").

As described above, colour code as shown in Figure 7 is exported by the print process unit 301 of print engine 3.Therefore, printing is worked as The aging over time of processing unit 301, cause the reduction of the density of output image, and the corresponding density of the colour code shown in Fig. 7 Also reduce.That is, even if working as, for example, when outputing the C- colour codes with 80% level of density, the density of the block of output is less than 80%.

By way of parenthesis, when print process unit 301 is formed by the electrophotographic image shown in Fig. 5 and output mechanism is and by reality Now, reducing the factor of the density of output image may include the reduction of optical density for the light source being exposed to photosensitive drums 12, use The reduction for the developing bias that the electrostatic latent image formed on to photosensitive drums 12 is developed, and it is developed in photosensitive drums 12 in transfer On tone images or the tone images that are needed in transmission belt 11 during the reduction of transfer bias that uses, etc..

Form is preserved in gradation data generation unit 103, the form is indicated when gradation data generation unit 103 is with pre- Determine density and output result (hereinafter, referred to as " desired result table ") of the image without reducing its density, as such as Fig. 7 institutes Result during the reading result of the colour code shown.Fig. 9 is the chart for the example for showing desired result table.As shown in figure 9, in ideal As a result in table, each YMCK pattern densities are associated with the gray value of the preferable reading result of instruction.In addition, the reading shown in Fig. 9 Gray value is also to draw gray value used during the colour code with corresponding pattern density shown in Fig. 7.

Gradation data generation unit 103 is given birth to according to reading result table as shown in Figure 8 and desired result table as shown in Figure 9 Into YMCK gray correction tables as shown in Figure 6.Especially, gradation data generation unit 103 is each in result table based on reading Each reading gray value generation such as Fig. 6 of each pattern density in each the reading gray value and desired result table of pattern density Shown gray correction table.

Preferable state is, for example, " 80% "-density pattern is read as the shape of the gray value of " 230 " as shown in Figure 9 State.On the other hand, as shown in figure 8, the gray value of the reading result of " 80% " pattern is " 220 ".In addition, as shown in figure 8, The gray value of the reading result of " 90% " pattern is " 232 "；Thus, for example, corresponding to the figure for being slightly less than 90%, such as 88% In the case of the output of the dot matrix diagram data of case density, the gray value for reading result should be " 230 ", i.e. the pattern of " 80% " Ideal density.

Therefore, in figure 6, " 230 " are set to " input gray level value " by gradation data generation unit 103, and corresponding to smaller It is set to " output gray level value " in the gray value of the pattern density of " 90% ".Should be " corresponding to the pattern density for being slightly less than " 90% " Gray value " can be by using the gray value of the pattern for drawing " 80% " and the gray scale of the pattern for drawing " 90% " Linear calculating that value is carried out and obtain, and be " 243 " in the example shown in Fig. 6.Gradation data generation unit 103 repeats This calculating, and the output gray level value corresponded to from 0 to 255 8- positions input gray level value is generated, it is as shown in Figure 6 so as to generate Gray correction table.

By way of parenthesis, in Fig. 6 according to the present embodiment, corresponding to each " input gray level value " each CMYK color it is " defeated Go out gray value " all it is identical.In addition, in fig. 8, corresponding to " the reading gray scale of each CMYK color of each " pattern density " Value " is all identical.In addition, in fig.9, " pattern density " corresponding to each CMYK color of each " reading gray value " is Identical.Such case is used for the purpose of ease of explanation, and due to being judged individually each color, between CMYK color Correlation can be different.

Next, the flow chart with reference to shown in Figure 10 explains the operation of the whole inspection equipment 4 according to the present embodiment.Such as figure Shown in 10, using during according to the check image of inspection equipment 4 of the present embodiment, master image processing unit 402 be based on from Dot matrix diagram data and gray correction table the generation master image (step S1001) that dot chart transmission unit 203 inputs.

Dot matrix diagram data is being transferred near the time for checking equipment 4 from dot chart transmission unit 203, thereon by beating Paper of the print engine 3 formed with/output image, which is sent to, to be checked in equipment 4, and reads the surface that equipment 400 reads paper, Reading image (step S1002) is obtained so as to read image acquisition unit 401.

When reading image acquisition unit 401, which obtains, reads image, check the control ratio of control unit 403 compared with test cell 404, and perform by the reading image obtained of reading image acquisition unit 401 and the master map generated by master image processing unit 402 The processing (step S1003) of alignment as between.

In step S1003, check that control unit 403 is extracted as shown in Figure 4 near the reference point extracted from master image Zoning image, and extract and read image and correspond to from the part of the image of the zoning that master image extracts Image, then the image extracted is inputted to comparing test cell 404, so as to obtain described by reference picture 4 in pixel To the difference of the pixel value of the respective pixel on the basis of pixel between images.Reference point is referred here in experience image shape The mark shown on into four angles in the region in the element with output.By way of parenthesis, during even if without this mark, such as Figure 16 B The shown pixel that can turn into mark can be utilized picture filter, such as angle to extract from image as shown in Figure 16 A Filter extracts.

Vertically and horizontally moving from the region for reading the image that image zooming-out goes out, checking that control unit 403 repeats Perform and carry out obtaining the processing of the result of calculation of difference for several times by comparing test cell 404, and determine to read carrying for image Region is taken, the total value of wherein difference is the minimum value in the opening position in the extraction region corresponding to master image.It is true by this way Position amount of movement between the extraction region for the reading image made and the extraction region of master image is determined to correspond to image Reference point position amount of movement.

Check that control unit 403 repeats identical to the multiple reference points extracted from master image and handled, and The final position that master image is obtained on the basis of each counted position amount of movement of these reference points and is read between image is moved Momentum.The method that can be used in the processing for obtaining final position amount of movement has, for example, using the counted of each reference point The method of the average value of position amount of movement linearly obtains image on the basis of the counted position amount of movement of each reference point Each part position amount of movement method.

On the basis of alignment is completed by this processing, check that control unit 403 performs and compare test, with using in step The master image obtained in rapid S1003 and the position amount of movement read between image are contrasted (step with master image to reading image Rapid S1004).Image will be read and pass through the image performed on being divided with given area size with the processing that master image is contrasted Each zoning alignment and perform.

Thus, check control unit 403 obtain compared test cell 404 and be defined as the position of defective image ( Hereinafter, referred to as " defective locations information ").In this way obtain the defects of positional information be shown in for example with inspection On the connected LCD60 of equipment 4 display device, or pass through network transmission to engine controller 2.

Check that control unit 403 reprocesses since step S1001, until all pages be included in print job Inspection has terminated ("No" in step S1005), and reaches step S1004's when all pages be included in print job When processing has terminated ("Yes" in step S1005), end processing.By this processing, according to the present embodiment to image The whole processing of inspection operation terminates.

The present embodiment to be intended to manage in this place in step S1001 at master image generation processing.According to this implementation The details of function included by the master image processing unit 402 of example and the processing performed by master image processing unit 402 will be under Explained in text.

Figure 11 is the block diagram for the internal structure for showing master image processing unit 402.Figure 12 is shown according to this implementation The flow chart of the master image generation operation of example.As shown in figure 11, master image processing unit 402 includes a small amount of level/a large amount of levels At the conversion processing unit 421 of (small number of levels/large number of levels), conversion of resolution Manage unit 422, color conversion process unit 423 and image output processing unit 424.By way of parenthesis, according to the master map of the present embodiment As processing unit 402 be by Fig. 8 shown in special equipment 80 (that is, be made up of according to the control operation of software ASIC hard Part) realize.

By be expressed as coloring/non-staining binarised image on perform a small amount of level/a large amount of level conversion process, A small amount of level/a large amount of levels conversion processing unit 421 generates the image with a large amount of levels.According to the dot chart number of the present embodiment According to being the information that to input in print engine 3, and print engine performs image on the basis of each CMYK binarised images Formed and exported.On the other hand, the reading image as the image to be checked is in three primary colors (red, green and blue) (RGB) Each color there is the image of a large amount of gray scales and a large amount of levels.Therefore, binarised image is first by a small amount of level/a large amount of levels Conversion processing unit 421 is converted into the image with a large amount of levels.As the image with a large amount of levels, for example, can use with The image that 8- positions CMYK values represent.

Figure 12 is the flow chart for the specific processing for showing master image processing unit 402.As shown in figure 12, a small amount of level/ A large amount of level conversion processing units 421 carry out 8- Bits Expanding processing (steps in a small amount of level/a large amount of level translation process ) and smoothing processing (step S1202) S1201.The processing of 8- Bits Expandings is that 0 or 1 1- positions data are expanded into 8- The processing of position, and " 0 " is converted into " 0 ", " 1 " is converted into " 255 ".Smoothing processing is by using such as Figure 13 to 8- positions data Shown smoothing filter carries out smooth processing to image.

By way of parenthesis, in the present embodiment, example is described, wherein print engine 3 is on the basis of each CMYK binarised images Upper execution image is formed and output, and includes a small amount of level/a large amount of level conversion processing units in master image processing unit 402 421；But this is only an example.Formed when print engine 3 performs image on the basis of the image with a large amount of levels During with output, it is convenient to omit a small amount of level/a large amount of levels conversion processing unit 421.

In addition, print engine 3 there can be following function, 1- bit images are not based on but based on the image of a small amount of level, Such as 2- bit images and perform image formed and output.In this case, it can be operated in the processing of 8- Bits Expandings.That is, In the case of 2- bit images, gray value is 4 values：0th, 1,2 and 3.So as to, in 8- Bits Expandings, " 0 " is converted into " 0 ", " 1 " is converted into " 85 ", and " 2 " are converted into " 170 ", and " 3 " are converted into " 255 ".

Conversion of resolution processing unit 422 performs conversion of resolution, so that by a small amount of level/a large amount of level conversion process The resolution ratio for the image with a large amount of levels that unit 421 generates and the resolution ratio one of the reading image as the image to be checked Cause.In the present embodiment, the reading image that equipment 400 generates 200-dpi is read；Therefore, conversion of resolution processing unit 422 will The conversion of resolution of the image with a large amount of levels generated by a small amount of level/a large amount of levels conversion processing unit 421 is 200- Dpi (step S1203).In addition, in conversion of resolution, considered according to the conversion of resolution processing unit 422 of the present embodiment The contraction of the paper exported by print process unit 301 adjusts the chi of the image after conversion of resolution based on predetermined multiplying power It is very little.

Color conversion process unit 423 is obtained with the figure by the converted resolution ratio of conversion of resolution processing unit 422 Picture, and perform the conversion (step S1205) of gradation conversion (step S1204) and color representation form.Gray scale in step S1204 Conversion process is the processing opposite with the processing performed as RIP processing units using the gray correction table shown in Fig. 6.That is, color Conversion processing unit 423 performs gradation conversion, on the basis of the gray correction table inputted by dot chart transmission unit 203 Recover the density that (restoring) is adjusted by RIP processing units 102.Figure 17 is shown at the gradation conversion in step S1204 The flow chart of the details of reason.As shown in figure 17, color conversion process unit 423 is given birth to first with the gray correction table shown in Fig. 6 Into inverse gray correction table (step S1701).Inverse gray correction table is changed according to the color conversion process unit 423 of the present embodiment The table of input gray level value and the specific color correspondence of output gray level value is indicated during gray value.Figure 14 is shown according to the present embodiment Inverse gray correction table an example.

When generating inverse gray correction table, color conversion process unit 423 is from by conversion of resolution processing unit Pixel (step S1702) is selected in the image of 422 converted resolution ratio, and according to inverse gray correction table pair as shown in figure 14 The pixel value of the selected pixel is changed (step S1703).The repeat step S1702 of color conversion process unit 423 place Reason, until being included in the picture by all pixels in the image of the converted resolution ratio of conversion of resolution processing unit 422 Element value is all changed ("No" in step S1704), and when the pixel value of all pixels is all changed (in step S1704 "Yes"), the processing of end step S1204 gradation conversion.

As described above, it is applied to according to the gray correction table of the present embodiment using as the close of the dot matrix diagram data of original image Degree is heightened responded with the reduction of the density to the image exported by print process unit 301 in advance.When overstocked based on adjusting During the dot matrix diagram data generation master image of degree, the master image is generated with the density higher than the image that should normally export.This is highly dense It is different from the pixel value of the pixel of reading image because density adjusts to spend master image, so as to which pixel value exceeds above-mentioned threshold Value, and the reading image is identified as being defective.

On the other hand, generated according to the master image processing unit 402 of the present embodiment based on gray correction table as shown in Figure 6 Inverse gray correction table as shown in figure 14, and by view data to be processed, i.e. with by conversion of resolution processing unit 422 The density of the dot matrix diagram data of converted resolution ratio reverts to the state entered by RIP processing units 102 before line density adjustment. Therefore, it is possible to eliminate due to the pixel value of density adjustment, and therefore can solve the problems, such as above-mentioned.

In other words, the inverse gray correction table shown in Figure 14 is used as corresponding to density correction by master image processing unit 402 The information of information corresponds to the master image for the density that the image before density correction was carried out by RIP processing units 102 to generate.

By way of parenthesis, identical processing can be by reversely using " output gray level value " in the gray correction table shown in Fig. 6 " input gray level value " replaces being generated inverse gray correction table as shown in figure 14 based on the gray correction table shown in Fig. 6 and being used being somebody's turn to do Realized against gray correction table.In this case, as shown in fig. 6, all 8- positions gray values from 0 to 255 not always It is present in " output gray level value " side；Therefore, it is necessary to supply the gray value being not present using linear calculating etc..

In addition, as described above, it is RGB color image according to the reading image of the present embodiment；Therefore, color conversion process list CMYK coloured images are converted into RGB color image by member 423 in step S1205, and the CMYK coloured images had been carried out Gradation conversion processing.Therefore, generate and the 200-dpi images with a large amount of levels of each pixel are represented (altogether with 8- positions rgb value 24).That is in the present embodiment, a small amount of level/a large amount of levels conversion processing unit 421, conversion of resolution processing unit 422 and color conversion process unit 423 be used as check image generation unit.

According to the control for checking control unit 403, image output processing unit 424 exports what is represented with 8- positions rgb value 200-dpi images, it is by by a small amount of level/a large amount of levels conversion processing unit 421, conversion of resolution processing unit 422 The processing carried out with color conversion process unit 423 is generated.Then, check control unit 403 by master image processing unit Alignd between the master image of 402 generations and the reading image obtained by reading image acquisition unit 401, and determine whether to deposit In defect.

As set forth above, even if working as is necessary based on density according to the change of the state of print process unit 301 Carried out adjustment dot matrix diagram data generation master image when, can eliminate density adjustment influence and by above-mentioned processing to The image of original image density carries out defect inspection.In other words, the density correction for the image that formed/exported can be corresponded to And generate master image.

By way of parenthesis, in the above-described embodiments, an example is described, wherein due to being exported by print process unit 301 The reduction of the density of image, the image density of dot matrix diagram data are added in advance by RIP processing units 102.However, this is only One example；Therefore, in the case where the density of the image exported by print process unit 301 is above being expected density, at RIP Reason unit 102 can carry out reducing the processing of the image density of dot chart in advance.

No matter which kind of situation, print process unit 301 exports colour code as shown in Figure 7, and gradation data generation unit 103 generate gray correction table as shown in Figure 6 on the basis of the reading result of the colour code obtained by colorimeter 110, so as to enter The appropriate gradation correction processing of row.In addition, the gray correction table generated in this way is input to master image processing unit 402, and the master image processing unit 402 carries out gray correction according to inverse gray correction table as shown in figure 14, so as to generate root The master image of the image density exported according to print process unit 301, and carry out appropriate image and compare test.

In addition, in the above-described embodiments, an example is described, wherein for each print job, job information processing The output gray level checking list of unit 101, and the master image processing unit 402 of gray correction table has been obtained by engine controller 2 Inverse gray correction table is generated when performing each print job.However, the gray correction table that RIP processing units 102 use is not Each print job is changed.

That is, only when the colour code shown in Fig. 7 is exported by print process unit 301, and reading result table as shown in Figure 8 is During through being generated according to the reading result of the colour code obtained by colorimeter 110, the gray correction referenced by RIP processing units 101 Table is just changed.Therefore, job information processing unit 101 need not be to each print job output gray level checking list；Job information Processing unit 101 may be structured to only when the gray correction table that RIP processing units 102 refer to is changed, i.e. only when having performed During reading of the output and colorimeter 110 of the colour code shown in Fig. 7 to colour code, ability output gray level checking list.

In this case, in principle, only when master image processing unit 402 is with reference to paid-in gray correction table and Generate and the inverse gray correction table that has stored from DFE1 new gray correction table is obtained by engine controller 2 when, at master image Reason unit 402 just generates new inverse gray correction table.So as to, only just carry out generating the processing of inverse gray correction table when needed, It is possible to more effectively control checks equipment 4.

In addition, in the above-described embodiments, an example is described, wherein gray correction table as shown in Figure 6 is input to In master image processing unit 402, and the master image processing unit 402 generates inverse gray correction table as shown in figure 14.Or Inverse gray correction table can be created on DFE1 sides and be inputted by engine controller 2 to master image processing unit 402.

In addition, in the above-described embodiments, describe example, wherein gray correction table as shown in Figure 6 and as shown in figure 14 Inverse gray correction table be different forms.However, the two forms before switching after gray value be associated with each other this point On be identical.Therefore, gray value all before and after generation conversion is all specific table as gray correction table and inverse gray scale school Positive table, and by by overturning answering for the front and rear gray value of conversion between RIP processing units 102 and master image processing unit 402 Used with direction, so as to which a table can be used by both RIP processing units 102 and master image processing unit 402.Thus, base The processing of inverse gray correction table is generated in gray correction table to be omitted, so as to reduce the workload of processing.

In addition, in the above-described embodiments, describe an example, wherein described by Figure 11 and 12 by a small amount of level/ A small amount of level that a large amount of level conversion processing units 421 are carried out/a large amount of level conversion process and by conversion of resolution processing unit The inverse gradation correction processing carried out based on inverse gray correction table is carried out after the 422 conversion of resolution processing carried out.It is being converted into After 8- bit images with a large amount of gray scales, gradation conversion processing is carried out first, so as to be based on inverse ash as described in Figure 14 Spend checking list and carry out inverse gray correction.

Carried out in addition, gray correction is the image (reduced image) based on the reduction for being converted into 200dpi；From And the quantity of pixel to be calculated is reduced, thus amount of calculation can be significantly reduced.

However, this is only an example；For example, density correction can be carried out before the 8- Bits Expandings processing shown in Figure 12 Processing.In this case operation is as shown in figure 15.As shown in figure 15, carried out when before the processing of 8- Bits Expandings at density correction During reason, not processed image is 1- positions CMYK binarised images on that point.So as to pass through ash using as shown in figure 14 The density correction of angle value correction is impossible.

Therefore, in the example shown in Figure 15, master image processing unit 402 sparse (thins out) comes from CMYK binary Change the colour element of image, so as to adjust density (step S1501).By way of parenthesis, herein, for example, image density via RIP at Reason unit 102 is heightened；Therefore, master image processing unit 402, which enters to exercise colour element, becomes sparse processing to reduce density.Separately On the one hand, in order to increase density, master image processing unit 402 needs colour element becoming uncoloured pixel (uncolred pixels)。

Step S1501 processing has been based on inverse gray correction table as shown in figure 14 and carried out.For example, for each CMYK Image, master image processing unit 402 calculate the colour element of given area and the ratio of uncoloured pixel, and determine given In region from the 8- positions gray value in the range of 0 to 255.For each given area determined by this way, colour element Become sparse on inverse gray correction table as shown in figure 14 according to " output " gray value corresponding to " input ".For example, work as " input " gray value is " 253 " and corresponding " output " gray value when being " 245 ", and colour element becomes sparse, so as to colour The ratio of pixel is changed into 245/253.Thus, it can be implemented according to the inverse gray correction of inverse gray correction table as shown in figure 14.

According to the embodiment, the master of the density correction corresponding to the image that formed and exported in a system can be generated Image, the system are formed by comparing by the image for reading paper the reading image that obtains and for inspection come check image With the result of output.

Although in order to disclose thoroughly and clearly, the present invention, appended right are illustrated on specific embodiment It is required that be not restricted to this, but be interpreted as including fall into it is set forth herein it is instructing substantially, can for those skilled in the art The whole modifications that can occur and replacing structure.

Claims

1. image inspection equipment, check by reading the image for being formed and being exported on paper and the reading image obtained, the figure As checking that equipment includes：

Image acquisition unit is read, is obtained by the reading image that is formed and exported the reading image that generates；

Check image generation unit, the information based on the image that formed and exported obtained from image processing apparatus, which generates, to be used for Check the check image for reading image, the information for the image that image processing apparatus generation will be formed and exported；With

Inspection result acquiring unit, based on the check image for being used to check reading image generated and read the difference between image Value obtains the determination result for reading the defects of image, wherein

Described image processing unit is according to progress image formation and the state correction figure to be exported of the image processing system of output The density of picture, to generate the information for the image that formed and exported, and

Check image generation unit, density correction information is obtained, corresponded to the density correction information generation based on acquisition by institute The check image of the density before image processing apparatus correction is stated, in the density correction information, the density of image is by the figure As the front and rear density value of processing unit correction is associated.

2. image inspection equipment according to claim 1, wherein

Described image processing unit changes the image with a large amount of levels that the density of wherein pixel is represented by substantial amounts of gray scale Into wherein gray scale amount less than the image with a large amount of levels gray scale amount the image with a small amount of level, with generate want shape Into the information of the image with output,

Information corresponding to density correction information is the density value phase of the wherein pixel represented by substantial amounts of gray scale that conversion is front and rear The information of association, and

After the information for the image that formed and exported is converted into the image with a large amount of levels, the check image generation is single Member generates check image based on the information corresponding to density correction information, and the check image, which corresponds to be handled by described image, to be filled Put the density before correction.

3. according to the image inspection equipment of claim 1 or 2, wherein

The resolution ratio for the image that the check image generation unit will be formed and exported according to the conversion of resolution for reading image, so Afterwards based on the information correction density corresponding to density correction information.

4. according to the image inspection equipment of claim 1 or 2, wherein

The figure that described image processing unit will be formed and exported based on the information correction corresponding to the density correction information obtained The density of picture, also, only when new density correction information be output it is defeated with the state correction according to described image forming apparatus During the density of the image gone out, the information corresponding to new density correction information is obtained, with based on corresponding to new density correction letter The density for the image that the information correction that breath obtains will be formed and exported.

5. image review systems, the reading image for checking the image for being formed and being exported on paper by reading to obtain is described Image review systems include：

Image processing apparatus, according to the state correction image to be exported for the image processing system for carrying out image formation and output Density；And generate the information for the image that formed and exported；

Image formation unit, the information based on the image that formed and exported carry out image formation and output；

Image fetching unit, by reading the paper generation reading image for being formed thereon and outputing image；

Check image generation unit, the information based on the image that formed and exported generate the inspection figure that image is read for checking Picture；With

Inspection result acquiring unit, based on the check image for being used to check reading image generated and read the difference between image Value obtains the result for the determination for reading the defects of image, wherein

The check image generation unit obtains density correction information, with the density correction information generation based on acquisition correspond to by The check image of density before the correction of described image processing unit, in the density correction information, the density of image is by image The front and rear density value of processing unit correction is associated.

6. check the image checking method of the reading image obtained by reading the image for being formed and being exported on paper, the figure As inspection method includes：

Reading image is obtained by reading the image for being formed and being exported on paper；

The information for the image that formed and exported is obtained from image processing apparatus, and generates the letter for the image that formed and exported Breath, described image processing unit are formed according to the density of the state correction of the image processing system image to be exported, described image Device carries out image formation and output；

Density correction information is obtained from described image processing unit, before the density of image is corrected in the density correction information Density value afterwards is associated；

The information generation of density correction information and the image that formed and exported based on acquisition is corresponding to density by described image Check image before processing unit correction；With

The determination result for reading the defects of image is obtained based on check image and the difference read between image.